The present invention refers to sealed bearings incorporating an inner race ring, outer race ring, rolling bodies arranged between the inner race ring and the outer race ring in one or more rows, and so-called built-in sealing members, whereby the outer race ring, at least at one of its sides, is equipped with a mounting groove for receiving the sealing member, the groove being situated inside the side plane of the outer race ring and being arranged to taper at an angle relative to the side plane.
The "life span" of a bearing is reduced by dirt and impurities penetrating into the bearing. The assembly of the bearing, on one hand, may occur in dirty surroundings, and the bearings may, on the other hand, during operation, be exposed to dirt, metal chips, and the like. Also, during use of bearings in continuous casting machines, rolling mills, paper making machines, etc., the bearings may be highly exposed to different kinds of impurities. This also places high demands on maintenance.
Thus, a good seal for a bearing in many cases can be most important, on one hand for increasing the life span and on the other hand for reducing the maintenance.
Known solutions for designing sealed bearings are based on two different principles, i.e., a seal can either be assembled onto a bearing or be built into the bearing. Embodiments of how a seal is assembled onto a bearing is shown, e.g., in Wittmeyer et al U.S. Pat. No. 4,790,543 and Asberg et al U.S. Pat. No. 4,755,067. The seal in these embodiments is constituted by two cooperating sheet metal rings, whereby at least one of the sheet metal rings is notch-joined into the outer race ring, whereas the other is fitted to the inner race ring. This solution, however, means that the seal will project outside the side planes of the race rings, which in some cases necessitates modification of the bearing housing and also of the mounting and dismantling tools.
According to the other alternative mentioned above, the seal is built into the bearing. In this case the seal does not project beyond the side planes of the race rings. Assembly of the seal inside one of the bearing side planes requires space and for this reason the width of the bearing itself can be increased, or, in the case with roller bearings, the roller length has been reduced.
In one known sealed bearing, the width of the bearing has been increased as compared to a corresponding unsealed bearing in order to maintain the carrying capacity. In that case, the seal is mounted in a radial groove formed in the outer race ring, where it is fixed with a locking ring, and the opposite side of the seal engages a tapering surface on the inner race ring. (It is also known to attach the seal in the outer race ring with some type of rubber lip.)
The attachment of the seal in a radial locking ring groove requires large axial space which means that the outer race ring necessarily will become wide if the carrying capacity shall be maintained. That is a drawback, as it is desirous to keep the bearing as small and compact as possible due to the particular uses for which the bearing is intended, and to maintain the ISO-width according to ISO standards.
Another drawback is that an attachment with a rubber lip does not give the high retaining force desired.
In spherical roller bearings, in contrast to others, the set of rollers may hit and dislodge the seal.
Purposes of the present invention include providing a sealed bearing having a built-in seal, wherein the attachment of the seal requires a minimum of assembly space; the outer race ring preferably should not be made wider as compared to unsealed bearings. The carrying capacity, speed ranges, and the like should also not be adversely affected.